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New Plants Shrug Off Salinity

Exposure to high salinity
is killing Yecoro Rojo (right),
a wheat cultivar that has
moderate salt tolerance. Plants
resulting from hybrid crosses
with W4910 (left) show much
greater tolerance of high salinity. (K10183-1)

Two new lines of salt-tolerant plants from ARS
researchers may someday prove to be a boon not only for wheat growers
but also for salt-laden wildland ecosystems. Salt tolerance in plants
is a prized trait. That's especially true in the irrigated wheat-producing
regions of the American West, where irrigation can accelerate buildup
of salts.

Salinity reduces yields by weakening or killing plants.
Nationwide, it's blamed for reducing crop yields by about 25 percent,
according to ARS research geneticist Richard R.-C. Wang. He developed
the new breeding lines, known simply as W4909 and W4910. The work has
already attracted the attention of researchers and plant breeders throughout
the United States and from several other nations as well.

Wang is with the ARS Forage and Range Research Laboratory
in Logan, Utah. He's working to demystify the complicated genetics of
rangeland plantsincluding some that are relatives of wheat. His
investigations are key to making hardier and more nutritious forages
for cattle and other livestock and for wildlife such as deer, elk, and
moose. In addition to providing forages for animals to graze, the improved
plants that result from the Logan lab's research could be used to revegetate
rangelands, roadsides, burned sites, or erosion-prone slopes.

W4909 and W4910 are the progeny of unique parents. One
parent contains genes from wheatgrass, a wild relative of wheat. The
second parent contains what's known as a Ph-inhibitor gene. That
gene squelches another gene, Ph1b, that would otherwise block
the transfer of wheatgrass genes into domestic wheat.

For the research, Wang collaborated with ARS geneticist
Steven R. Larson of the Logan team; Catherine M. Grieve, an ARS plant
physiologist at the ARS George E. Brown, Jr., Salinity Laboratory at
Riverside, California; Michael C. Shannon, formerly at Riverside and
now with ARS' Pacific West Area Office, Albany, California; Abdul Mujeeb-Kazi
of the International Maize and Wheat Improvement Center; and four visiting
scientists from ChinaZanmin Hu, Xiaomei Li, Jiyi Zhang, and Xueyong
Zhang.

Wang and his co-investigators are the first to use the
Ph1b gene-inhibition technology to incorporate, into wheat genetic
material, genes borrowed from another plant species.

The new plants serve as a handy model for discovering
the function of wheatgrass genes. Explains Wang, "Once the wheatgrass
genes are moved into experimental wheat plants, the genes may become
easier for scientists to access and decipher. This approach not only
serves as a starting point to improve wheat and rangeland plants, but
helps us learn more about wheatgrass genes at the same time."By
Marcia Wood,
Agricultural Research Service Information Staff.

This research is part of Rangeland, Pasture, and Forages,
an ARS National Program (#205) described on the World Wide Web at http://www.nps.ars.usda.gov.